Thicker than Water
by GrimGrave
Summary: Requested by Olho07. AU. A tale of two sisters with a bond stronger than family, but its hidden away under lock and key. Until, that is, their own mother catches wind of what's going on formulates a plan to bring them together... Rated M to be safe due to mature implications.


Disclaimer: _Kill la Kill_ and all characters associated belong to studio Trigger and not GrimGrave, who do not earn money by writing fiction.

Requested by Olho07.

 _An abundance of thanks to_ _ **Supreme Distraction**_ _for being my beta-buddy! ^^_

 **Thicker than Water**

It was an early evening in autumn when Ragyo Kiryuin – CEO of one of the most influential textile companies in the world – made her way back to her bedroom, clad in a fancy nightgown of silvery-white colour, brooding. What dwelled inside her mind were thoughts she had duelled with many a time ach and everyday for the past few years, ever since her darling daughters had begun to mature.

Her daughters – an older girl named Satsuki and a younger girl named Ryuko – were now eighteen and seventeen respectively, and it was a few years prior that Ragyo had caught wind of what lay beneath the surface of her children's relationship: an unseen bond; an affection that was more than love for one's family.

She had dismissed it at first, thinking that she had misinterpreted signals that weren't even there and swiftly moved on. However, as time passed, the signals not only were there, but the mother realized that she had interpreted them correctly: her daughters cared greatly for one another —more than family members _should_.

Ryuko and Satsuki were inseparable. If one wanted to take a bath or a shower, the other insisted to take one as well – which was fair, considering that it saved water and the bath was large enough to accommodate more than one user – it was huge enough for an abundance of people! – but they barely bathed alone. The sisters would also be as close as possible, either while they watched television programs or ate dinner (and lunch and breakfast…) and last, but not least, there were the looks they exchanged.

Ragyo had lost count of how many times she had caught them stealing glances at one another, the look in those two pairs of blue orbs being coquettish and longing – a desire for something more that they didn't dare reach out for.

And yet it was but the tip of the iceberg.

At first, the mother of the household had been baffled and concerned (as anyone would be) but as time passed she began to find their mutual-yet-clueless affections amusing. And after all, she could relate to them; she knew the tingling sensation that settled between one's legs and heated one up at the touch of another woman, and the addictive pleasure that only the fairer sex could grant.

That's why, some time back, when her children were still very young, Ragyo had divorced their father and her husband and had gotten herself re-married to a young woman named Nui Harime. She was in her mid-twenties (closer to thirty at this point), which was younger than Ragyo, but their love had been at first sight.

But their love was different. She and Nui weren't related by blood – but Satsuki and Ryuko were. And yet, the thought of it had her smirking at the lewdness of it, but it was far from (just) a naughty idea. After all, the two were quite a match, and Ragyo was no stranger to going against the norm.

That was why she decided to start putting her little plan together.

 **x.X.x.X.x**

"Hououmaru," Ragyo said as she stepped inside her office the next day, a content smirk on her face.

Rei Hououmaru – a cute young African woman and Ragyo's secretary – was by her boss' side at the blink of an eye, ever-alert and at the ready. "Yes, Lady Ragyo?"

Her calm and dedicated nature, along with her cute-yet-gorgeous looks made Rei Ragyo's favourite employee, whom she couldn't help but to tease and shamelessly flirt with at times – and occasionally feel up, a fact that Nui had delighted in participating. The African-Japanese woman's devotion ran deep; she always did as told without question, and happily so!

"When will my daughters be back from the academy today?"

The light-purple-haired woman tapped away at her tablet for barely a few seconds. "Their last subject for the day is scheduled to end in about 27 minutes, ma'am."

The older woman mulled that over. "It was today they had their tests in both math and history, no?"

"Correct, Lady Ragyo."

"Good. That'll help. I do hope my darling children did well." Her maroon eyes shifted over to the large window that looked over the vast city. "Did you do what I asked of you?"

"Yes," Rei replied, looking down at her tablet again, adjusting her aviator sunglasses. "I booked the three rooms at the Beppu Onsen inn in Ōita for the weekend, and your private plane is ready and waiting. I also had Soroi pack yours, Lady Nui's, and my bags for the stay, as well as prepared Miss Satsuki's and Miss Ryuko's bags to save time."

"Perfect. Well done, Hououmaru." The CEO chuckled and reached down to teasingly cup a handful of her secretary's rear through the latter's white shorts, squeezing. "This is going to be fun. My perfect little angels will be truly happy once this weekend is over."

"I whole-heartedly agree, ma'am," Rei replied, smiling alongside her boss and fighting the vague red tint that was spreading over her face.

 **x.X.x.X.x**

"You're **what?!** " Ryuko spat out her dinner in disbelief, not giving a damn about the mess she made as a result as she stared wide-eyed at her mother, chopsticks clattering on the table.

"I believe we must've misheard you, mother," Satsuki said, already in the process of wiping her little sister's mouth with a napkin.

"You heard your mother correctly," Nui said with a giggle.

Ragyo snickered. "Your ears work just fine, my dears. Since you both did very well on your tests, your mother and I think it's only fair that we reward you, no? That's why we're staying at an onsen inn in Ōita. Doesn't it sound nice?"

The youngest daughter's face lit up with a grin. "For real? This is awesome! Yes! Oh, does this mean we don't have to do our homework?"

"Ryuko!" the older daughter exclaimed. "You shouldn't be so quick to dismiss your studies! You need to—!"

"It's alright, Satsuki," their mother interrupted. "While I'm glad you're keeping your sister in check, Student Council president, you shouldn't deprive yourself of some relaxation. You two just enjoy your dinner for now – we'll leave in a couple of hours."

Satsuki's eyebrows knitted together. "We're leaving tonight? Surely we can wait until tomorrow—"

"Hououmaru has already prepared for our stay," Ragyo said calmly. "Besides, opportunities like these don't come very often. When was the last time we enjoyed ourselves for more than just a day?" She chuckled and wiped her mouth delicately with her napkin as she got up from her seat. "I still have some minor business to take care of. Enjoy your dinner, my darlings." She held out her hand for her blonde, bubbly wife. "Come, Nui."

"Gladly~" In an instant, the younger woman was embracing her whole arm instead, nuzzling into the pale-haired woman.

With that, the older women left, leaving their girls to themselves.

Azure gazes stared back and forth at each other, the sisters sitting in silence for what felt like hours.

"So," the younger girl said, breaking the silence. "Hot springs, huh? It's kind of weird how we haven't been to one yet…"

"Mother always insisted we didn't need to, since our bathhouse is not too different," Satsuki replied. "But I will admit, it does sound nice to get away for a while…" Her eyes strayed to her left, silently appreciating her sister's form: while not athletically built, Ryuko's physique was fit and slim enough, and her face was beautifully framed by black bangs and a single left, red highlight.

"Yeah!" the aforementioned younger sister exclaimed. "And no homework to think about—just a good bath, new environment, and pleasant company."

"Pleasant company…" Satsuki said. The corners of her lips curved neatly upwards in a smile. "Yes, very much so."

The older sister chuckled and tucked a few long strands of hair behind her ear when Ryuko glanced over. Satsuki had always been a proud person who carried herself with a calm and aloof air around her – mostly the latter when dealing with people not particularly close to her – but underneath the seemingly-cold persona was kindness and warmth that only those really close to her knew; one of them being her younger sister, who looked away with a faint blush and a smile.

 **x.X.x.X.x**

The CEO stood in front of her office window, gazing into the distance. "How did they seem?"

"Nothing new: they eye each other up when the other isn't looking, and the idea of spending the nights together was positively met," Rei answered, adjusting her sunglasses.

"Perfect," she replied, petting her blonde wife who was still cuddling against her. "And the sleeping arrangements?"

"Miss Satsuki and Miss Ryuko will be sharing a room, while you and Lady Nui will share a separate one, as will I."

"Tee hee! I can't wait!" Nui exclaimed. "I can't wait to tease them when they're finally together!"

The white-haired woman chuckled and chastely pressed her lips against the blonde's temple. "Now, now, dear. Save it for at least next week; let them have some time together."

She playfully pouted. _"No promises~"_

 **x.X.x.X.x**

"And this will be Lady Satsuki's and Lady Ryuko's room," the secretary said as she opened up the door. The inn was a combined style of luxury and humbleness with their rooms featuring the basic, simple needs such as beds, nightstands and a kotatsu, but also a stylish minibar (in the grownups' rooms) amongst a few other things.

"Sweet," Ryuko said with a grin, inspecting the room. "And we're going to spend the entire weekend here, mom?"

"That is the plan," Ragyo replied. "It has gotten late however, so let's call it a night. Sweet dreams, my dears."

"Goodnight, mother," Satsuki said as their mothers left. Her expression was impassive until the door clicked shut, and she smiled warmly. "So… Here we are."

The younger sister nodded, still grinning sheepishly. "Yeah… It's going to be fun." She quickly averted her eyes. "I guess we should… uhm… get ready for bed. It's late."

"Agreed," the older sister replied, already in the midst of unpacking when she noticed Ryuko from the corner of her eye undressing herself, Satsuki ceased.

Creamy pale skin bared itself for her with only the green-and-white striped underwear covering the essentials, to the long-haired sister's disappointment. Heat rushed to her face and core, the hot desire to reach out and caress her sister's forbidden fruits damping her panties—

"Sis?"

Azure eyes widened as Satsuki forcibly tore her gaze away. "Yes?"

"You were staring, just now…"

"There was something I wished to say, but I forgot," she lied. "It was probably nothing."

Ryuko rolled her eyes with a low coming "whatever," but as soon as she knew her older sister wasn't looking, she ogled her – watching Satsuki unbuttoning her shirt with bated breath – and bit her lower lip in forbidden anticipation. It was a good thing they had separate beds – and a good thing Ryuko had spare underwear with her.

 **x.X.x.X.x**

"The water feels _sooo_ good~" Nui exclaimed contentedly as she stretched her limbs underneath the warm waters. The wives of the Kiryuin household had wasted no time in heading towards the springs after a short breakfast. The hot springs were bared to the relatively chilly sky, offering a view of the city in the distance.

"Don't get too comfortable, Nui darling," Ragyo said with a chuckle. "We have to leave the lovebirds to themselves once we're done. How are they coming along, Hououmaru?"

"Due to them being very close, their mannerisms and demeanours suggests there's a high amount of pent-up emotions. I estimate that they only need a little nudge in the right direction, Lady Ragyo," Rei replied from across the pool of water. She was blushing, not from the water, but from her boss' hand groping a firm, brown, malleable peak.

"Sweetheart, they're coming!"

"And not a moment too late," the CEO remarked with a smirk. "Look at them glancing at each other. They haven't even gotten rid of their towels."

"Do they not bath together all the time?" Rei inquired and held back a content sigh.

"They must be even more aware of each other now," the blonde said, giggling. "I just want to tease them!"

The daughters made their way to the shelves and hesitantly discarded their towels, their nude forms bared for each other to see – two sets of blue orbs wandered, eyeing each other up and down with hidden appreciation for a fleeting moment. Milky white cheeks were flushed red as they looked away and hurried over to the spring.

The trio of elder women had to stifle their laughter.

"Well?" Ragyo asked, having composed herself. "Isn't this wonderful?"

Satsuki nodded. "Yes, mother…"

"Hell yeah it is!" Ryuko said happily. "You don't say 'no' to a change of scenery!"

 _´Time to push them in the right direction,´_ their mother thought, snaking an arm around her young wife. "I'm glad to hear it, my dears. But please, don't feel restricted to the onsen; I hear they've finished constructing new shopping malls downtown, so please indulge yourselves…" Her full lips curved upwards into a sly smile. "Who knows, perhaps you (might) spot some cute boys?"

The sisters' eyes bulged and their lips parted to let out audible gasps, the younger of the two blushing even harder. "W-what are you saying, mom?!"

"Hmm? Why are you blushing, Ryuko? You two are at that age now. Surely you must've met the occasional boy who has caught your fancy?" The CEO let her hand gently caress Nui's side before travelling upwards, resting on the blonde's shoulder and pulling her close. "Or maybe you take after your mother and settle with a cute girl instead? Men can be… troublesome…"

Her children didn't say a word.

 _´Bingo´_ "Come to think of it, Ryuko, you have that friend who is rather clingy, as I remember… young Mankanshoku, was it? She's your classmate, no? And you, Satsuki, your friend Jakuzure—"

" **NO!"** the daughters of the Kiryuin household shouted simultaneously and they exchanged looks – shock, confusion, and awe – for but a moment before continuing, their faces hot with shame.

"M-Mako is… I think she's into our disciplinary committee chair… I don't mean that I –! … I don't…!" She buried her head in her hands, groaning audibly.

Meanwhile, Satsuki crossed her arms over her chest, refusing to meet her mother's eyes. "… I think of Nonon as a friend. Nothing more."

"Of course, of course – I didn't mean to pry," the silver-haired woman stated. "However, I do find it particularly odd that neither of you are even talking about dating. No gossiping about potential love-interests or anything, really; it's a shame. After all…"

Ragyo got up from the water, revealing her bare body – from her slender ankles to her voluptuous chest – with Nui in tow, gently dragging her own fingernails against a pale stomach. "While men can be of service, only a woman can truly understand and know how a fellow woman works; her mind-set, her desires… everything there is."

Nui cooed at her wife's touch, legs shaking and back arching, mewling continuously as the older woman caressed sensitive skin in front of her step-daughters and their secretary.

"Surely you have at least considered the option? There's nothing wrong with pursuing the same gender."

Ryuko looked away, her whole face red as a tomato. "M-mom?! Knock it off, what are you doing?!"

"This is disturbing, mother," Satsuki added. "Being bare is one thing, but… this? Have you no shame?"

 _´Perhaps using their mothers as an example was not as effective as I had hoped,´_ Ragyo thought. "I told you, there's no shame in not preferring men, Satsuki. But maybe it'll be easier to understand if I do this." She gestured at her secretary. "Hououmaru."

The African woman's eyes widened and for the first time since her service in the Kiryuin household, she disobeyed. Rei slowly shook her head.

"Hououmaru," the CEO said, this time more firmly. The secretary sighed and resigned herself to her fate and got up from the spring. Her light-purple hair was loose and fell down past her shoulders as she displayed herself for the Kiryuin daughters. "See? Hououmaru is a fetching woman, isn't she? Surely you would like someone similar to share your bed—"

"Enough, mother!" The oldest daughter shot her mother a firm glare. "I have no idea what you're on about, but please just stop this foolish demonstration! We appreciate your support, but don't force anything onto Ryuko and I, right, Ryuko? … Ryuko?"

The younger sister, red as a beetroot, was still gawking at their secretary, who looked like she was ready to burst with humiliation.

"Ryuko!" Satsuki blocked her sister's view with her hand and pulled her close, still glaring at their mothers. "Mother, make her stop!"

"Very well. Enough, Hououmaru," Ragyo said with a frown. "We'll let you two be. Just… Think about what I've said. It's for your own good."

The older sibling continued to glare until the other women were gone. "Honestly… that mother of ours… What is she even up to?"

"Hell if I know," Ryuko replied, crossing her arms. "A-and furthermore, I was staring because… Because I was surprised how slim Hououmaru was! I am n-not interested in her, got it? Or Mako for that matter!"

"…And why are you telling me this?"

"I… I don't know! I don't want you to get the wrong idea, I guess. So sue me!"

"Well…" Satsuki said. "…I guess I should clear the air and say that there's nothing between me and Nonon either. In case you were curious."

"…Good."

"Mm."

"Because," Ryuko stated. "I'll chase off anyone – man or woman – who gets too close. Just so you know."

The older sibling laughed softly. "Funny. I was going to say the same to you."

"R-really?"

"Of course. You're my sister – it's my job to keep you safe and sound. Can't do my job if you're in the arms of someone else."

There was a silence following that statement, and the sisters exchanged looks of sheer disbelief – contemplating the meaning behind those words – until Ryuko finally said: "…Then… Who am I t-to keep you f-from doing your job? I guess I have to forever be by your side…"

"What did you say?"

The younger girl looked away. Her heart was pounding against her ribs, pulse rising, and her words finally sunk in and she realized just what had slipped out. "F-forget it! I'm just—!"

"No," Satsuki said. She gripped her sister by the wrist and pulled her close, forcing them to meet eye-to-eye. "This is important, Ryuko. I want to hear you say it again. I dislike uncertain relationships."

"…I can't."

"Please, don't shut me out, sister." The older girl loosened her grip on her sibling, but reached out and cupped her cheek. "We've always been close, haven't we?"

"Tch… I… I want to be forever by your side, Satsuki. I care about you, even if you can be stuck-up…"

"And you're adorable, even if you can be obnoxious," Satsuki replied. She gently held Ryuko by her shoulders, blue twin pools peering amiably.

"Sis…" The younger sister hesitantly reached out and touched smooth skin. "I… Gah! What have you done to me…? Whenever I'm even remotely close to you, I…"

"That would be my line. I've always cared about you, and yet… Being with you as your sister didn't feel enough – being related by blood isn't enough." She chuckled. "We're certainly a pair, aren't we?"

"Sis…"

Hands travelled up and down, carefully caressing hot bodies as if they were porcelain. Hearts beat as one as feelings were unearthed, rising to the surface.

"Ryuko…"

Arms wrapped around waist and neck, pulling the sisters together into a mindless, euphoric kiss that spoke louder than any words possibly could.

 **x.X.x.X.x**

"Tee hee! Looks like it worked after all, darling~"

The trio of women peered from behind the wall, gleefully witnessing the union of the younger girls.

"I'm glad," Ragyo stated. "Seeing my perfect little darlings together is truly heart-warming… Despite their differences, they're a perfect match for each other."

"I fully agree, Lady Ragyo," Rei agreed joyfully.

"Hououmaru, Nui, I think it's time we took our leave. They will with no doubt be alone for a while." And with that, the older women left, spending the day not disturbing the young girls. After having spent years of silence, it was only fitting that they were left to express themselves to make up for lost time.

Ragyo knew that there would come a day when inheritance of the corporation would come into question due to lack of grandchildren, but she filed that away for later. What mattered now was that her children could finally be true to not only themselves, but to each other. Blood was thicker than water, and it was that blood-tie that would ensure the sisters a lifetime of happiness to come.

However, poor Rei found out the hard way that the libido of the Kiryuin household was not easy to quench – something the daughters really had taken after their mother –and therefore spent the weekend with a pillow covering her ears.

 _ **The End.**_


End file.
